Topic 8 - New Shapes and Patterns

Partial Shapes

You don't always have to complete a shape by turning 360 degrees. Sometimes it is useful to have a partial shape that we can use in other ways.

Part of a circle is called an arc:

REPEAT 20 [FD 4 RT 6]

This draws an arc - how many degrees? A number of shapes can be built up from partial shapes, for example a square cross with semi-circles in place of straight lines.

Rounded Rectangle

• Write a function to draw an arc suitable for adding to the corners of a square
• Write a function to draw a rectangle with rounded corners using the function above

Cross

• Write a function to draw a semicircle.
• Write a function to draw a square cross with rounded ends using the semicircle function.

Star

• Write a function to draw an arc that will complete a five-pointed star with soft-corners.
• Write a function to draw the five-pointed star and use the new function to add the rounded ends.

Flower

Use one of the arc functions to create a flower with petals and a suitable middle. Add a stalk.

Clouds

Use the arc functions to draw one or more clouds. Try regular clouds first then see if you can make an irregular one.

Moon

Write a function that draws and fills a partial moon (where the shadow of the earth hides part of it).

Patterns

Now that we have functions for SQUARE, HEXAGON, and so on, we can use them to draw patterns.

Type in:

TO PATTERN1
REPEAT 12 [SQUARE RT 30]
END

And then the function name: PATTERN1

Or something slightly different:

TO CIRCLESQUARE
REPEAT 24 [SQUARE PENUP FD 20 LT 18 PENDOWN]
END

Type CS to clear the screen and enter the name of the new function: CIRCLESQUARE 

Here is one more example using the HEXAGON function written earlier:

TO CIRCLEHEXAGON
REPEAT 36 [HEXAGON PENUP FD 10 LT 10 PENDOWN]
END

You don't need any more examples - you can make up your own!

Exercises

Try as many of the patterns from the photocopy sheets as you can.

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